Every time someone quotes that the devils believe they relate it to salvation in relationship to justification which is handling that verse irresponsibly. The devils believe there is one God and no other and they tremble. That is all that means and there is no reading into it as part of the context. Jesus did not shed his blood for the sin or iniquity of devils, he shed it only for those who were created in his image and became part of the fall through Adam. There is no application to salvation or mental assent to discredit what God does when he saves a sinner by grace through faith and to do so with devils is a terrible interpretation.
Having an active faith is not a by-product of salvation or even having the love of God active in our heart on a continuous basis. Having our sins washed by the blood of Christ and being justified once and forever is a by-product of salvation and we have that forever in Christ.
Yes, they believe in one God and tremble. Apparently, it would seem that mere believe or fear of God is not enough. It says that a faith active through love is the only thing that matters to Jesus. What is more apparent is that their believe does not have active love. So, if it is acts of love which distinguish one's mere believe from active faith, then that is what distinguishes the demons mere believe from someone who has faith Jesus finds worthy, a faith active through love.
Of course Jesus did not shed His blood for demons, but we can see from that what a mere believe will get one, it has no value to Jesus. It was a gracious act from God to save sinners through faith and not deeds of the flesh, but a faith without works is dead, a mere believe. Of course an active faith is not a by-product of faith, but, nevertheless, it is a by-product of one putting his faith into action.
If one is justified (found innocent) once and for all, then tell me, would you preach lasciviousness? NO!!!! Why not? Could it have something to do with God's known Will and what He says about those who are lawless/anti-law (doing what is opposite of what the Law says is good before God) and how they will not inherit the Kingdom of God? Yet, if one is justified once and for all by mere believe, then why would the Spirit inspire the following:
Rom 2:13 For not the hearers of the law are just before God, but the doers of the law shall be justified"?
Rom 2:14 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves:
Rom 2:15 Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another; (Does not the Law have a role in the Christian life? Does not even our conscious concur with this fact?)
Rom 2:16 In the day when God shall judge the secrets of men by Jesus Christ according to my gospel.
Rom 2:17 Behold, thou art called a Jew, and restest in the law, and makest thy boast of God,
Rom 2:18 And knowest his will, and approvest the things that are more excellent, being instructed out of the law; (Does not the Law instruct us as to what His Will is for us?)
God has a path which leads to Him. Certainly, Jesus did not abolish that path, when all-in-all, it says that God wrote that Law upon our hearts. Jesus did not come to destroy His Father's Will, but to uphold the same through love and to teach others of His Way to the Father, spiritually....